Backing clamp for trailers



Oct. 14, 195 w. c ANDERSON ETAL 2,613,946

BACKING CLAMP FOR TRAILERS Filed March 25, 1951 2 SHEETSSHEET l Inventors WCarl flnderson a SydneyL.Dewey "d Gttorncgs 1952 w. c. ANDERSON El'AL 2,613,946

BACKING CLAMP FOR TRAILERS 2 SHEETSSHEET 2 Filed March 25, 1951 Summers WICa/rl Anderson w SydneylLDezz/ey '25 B o /zw,@g;& M

Gttornegs Patented Oct. 14, 1952 UNITED. STATE- S; .Y

BACKING; CLAMP FOR.-- ,'IB AII 4EB,Sg. W$Carl Anderson and-Sydneyii. Dewey;Qanton;

Ohio;assignors-tog-The Union' -Metal Manufao-- turing::Oompany-,=-- Canton, Ohio; atcorporation: -v ofQhiofl ApplicationuMa'rch 23;.1951, Ser1a1:No.t2 17;2s -4;;

4= Claimse (c1. 280 -33;05')

1 o. The, invention relates generallyto tractor and trailer combinations for transporting-heavy loads,

and more particularly to; a novel clamping, mechanism used in-b'acking atractor and trailer combination; of the type shownin U. '8. Letters In'general terms, the invention=is-embodiedin- Patent'No; 2A66;194; issued April 5; 1949; means'for clamping-atrailer-bodv-toits-'swiveled: The trailer of such a combination has a. undercarriage to prevent-- relative movement swiveled, undercarriage, and, the; operation of therebetween; said means-comprising--an-upper-- backingthe combination around a curve,. as jaw-fixedon'the frame of the undercarriage and illustratedin'Figs.13-18 andvdescribed' beginning a movable lower-jaw; said-jawsadapted to clam-pin line 400i columngof said patent, requires a extension"oftheififth w l pl t s, 11111911!Abe-4w certairr'amount of skill and practice on thejjpart ing a lever"operatively-connectedto'the' movable1 of the driverof the vehicle; because of the pivotal j W' and p at e the: fi ed. j w?" connection between the= trai1er and its under: p ctu n t er' ther ndofi carriage; Moreover, in backing around curves aid-l ver. ofvarious-radiior inb'acking in a substantially Referring 0 t a'wings in--which;'a preferred straightline; the tractor mustbe maneuvered, embodiment w by -w r;-0f'- mp1er--' differently for each set of conditions or the- Figure 1 isa fragm ary n itud na ls ctractor-trailer combination will jackkniiei? 131011811 View showing'the fifth Wheel Connect/ii!!!" Ithasbeen'found' in actual practice that, after. 20 between a trailer and ia e: the-combination has been started in the, general" g: 2 is a-fragmentary pl -v wr r f; direction in which it is desired tobaok, if the s an enlarged'fragm y ud undercarriage is lockedpr clamped to the trailer, Sectional View "Similar 0 87 the-backingo operation is materially facilitated. Fi 4 is aplan sectional view-asunline -4", and-requires much less skilla'ndpractice onthe 3; part of thegdriver than when the ,undercarriage Fig? 94 fra mentary, Sectional viewraswnr' israllowed toswivel. However, theclamping 111185-45; F 3; d" meansishould be adaptedjto yield somewhat un-t Fig. 6 is -afra m a yf iv ew- ..0nt. der abnormal'turning loads. to prevent damage line 6'-6, v to the-tires'in theeVentthecombination fjack: (t Asshown'kin-Figsl tp atform" kniiesm 1 during. the backing. operation 0 I0 preferably has tapered longitudinal ribsr'lron" Itjisanobjectof the present invention to proits underside, r e-carri d'on t eends" videinovelmeans for clampinga trailer and its of fifth Wheel io e'rtrlmnion is .p swiveled undercarriage against relative movej urnaled in a central: bearing;- l 4 and? ndb'ear-w ment duringbacking 35 ings I5 which are-mounted-in bracket -plates;I6)- Another-object is to. provide. novel clamping a T attached a 'by-w ldin to he upp fifth; means-adaptedto'clamp,the, fifth wheeljplate of wheel plate l8. The central bearing ST D" the trailer and the undercarriage together. ported bythe-upper-end-ofthekingbolt le-whichI A further object is to provide a novel clamping is: mounted in the frame--of-the undercarriage; Ineans applying a predetermined amount of grip- 40 indicated generally at 20; I pingiorce to the trailer fifth wheel plate so as The;-kingbo] t [9 i's-joumaledi r l bushing it rm l y to vprevent relative urning'ofthe unmountedwithinwebplates- 22in the frame-20; dercarriage', while permitting some relative turnd th 1 end of .ct t is rotatably) ing;:underabnormal turning force; clamped againstvthe-bottom'or said plates-by' a A still further object is to provide novel means n t -z a d f washer 24 c a t i wheels. forg frictionallyclamping the trailer and its p1ate25 is 'supported ontheupper endsr fxth g. swiveledgundercarriage against relative turning plates 22 and additional web plates .26 inhth a movement; said means being" operative from the undercarriage frame; Abronzezbearingringi21 wi ev may. be brazed to the; lower fifth wheel; plate; 25 Theseand v th robjects are accomplished by for.v rotatably; supporting, thaupmnfifth .wheel 5 theriparts; improvements, combinations and arrangements: comprising the present invention, a

preferred; embodiment of which is disclosed in H mode of: carrying out-the invention; the mature of the invention being set forth-inthe-following} general statement; and" the scope; of ftheinvention being defined in the-appended-claims.

plate l8 thereon. Thus,the,undercarriagejrame swivels about the king. 7 bolt?! 9 to allow-relative;

turningin .a horizontalplanegbetweenithe under-.,. carriage and the trailer platformygandi atithe same time a limited amount of rocking of the carriage in a vertical plane about the trunnion I 2 is permitted.

The side members 28 of the undercarriage frame, between which the web plates 22 and 26 are connected, may be tubular and extend forwardly and convergently over a dolly indicated generally at 29, which is resiliently mounted on the front axle 30 of the undercarriage by springs 3|. Above the dolly the side members 28 are connected by transverse upper and lower plates 32 and 33, and vertical web plates 34, and the front end of the frame is rotatably supported on the bearing plate 35 of the dolly by means of the pivot bolt 36. A cover plate 31 is detachably connected to the side members 28 above the pivot bolt 36.

The construction of the front end of the undercarriage frame and the dolly 29, and the connections therebetween are described in detail in Patent No. 2,466,194, and need not be further described herein because they form no part of the present invention.

The novel clamping means of the present invention are preferably applied to an extension of the upper fifth wheel plate l8. As shown in Fig. 2, a flared extension plate portion 38 extends forwardly from the upper fifth wheel plate l8, preferably in the same plane, and may terminate in a transverse edge portion 39. The extension portion 38 may be formed integrally with the fifth wheel plate l8, or may be welded on to a circular fifth wheel plate at its arcuate edge as indicated in dot-dash lines at 48 in Fig. 2, which would be the case in the event that the backing clamp is applied to an existing trailer having a standard circular fifth wheel plate.

The extension portion 38 preferably has a pair of vertically spaced resilient sector plates 4| welded to its outer edge portion 39, for extending between the upper and lower jaws of the novel clamp means indicated generally at 42. However, it will be understood that, within the scope of the invention, the portion 38 may be extended continuously to terminate at its outer edge between the jaws of the clamping means. As indicated in Figs. 1 and 2, the lower resilient sector plate 4| is provided with a series of access holes 44 to permit welding the inner end portions of the sector plates to the outer edge 39 of the extension plate, and to permit the escape of mud, dirt, and other foreign material which may enter between sector plates 4 I.

The upper jaw 45 of the novel clamping means is preferably a casting which is substantially U- shaped in plan, and has outer cars 46 which are rigidly attached by screws 41 and 48 to the vertical flanges 49 of angular brackets 50 secured as by welding on the top surfaces of the side members 28 of the undercarriage frame. The ears 46 are connected by transverse webs 5| to a central rectangular box portion 52 having transversely spaced ears 53 extending downwardly therefrom. A pivot pin 54 is mounted in the ears 53 and held against accidental removal by a set screw 55, and one end '56 portion of an operating lever 51 is journaled on said pin between the ears 53.

The lever 51 preferably tapers laterally inward from the end portion 56 to a vertical flange portion 58 at its other end, there being upper and lower laterally tapered ribs 59 between the ends for reinforcing the lever. The flanged end 58 of the lever is preferably provided with a circular boss 60 carrying a pivot pin 6| to which is connected a clevis 62 preferably attached to the piston rod 63 of a conventional air cylinder 64, although it may be actuated by other power means. The air cylinder 64 is supplied with compressed air with a hose connection 65 from a usual compressed air supply reservoir (not shown). Preferably, the cylinder 64 is attached as by bolting to the flange 66 of a bracket 61 carried on the web plate 26 of the undercarriage frame.

The air supply to the cylinder 64 may be connected to a separate operating valve in the cab of the trailer, or in the alternative, the operator may temporarily disconnect the air supply line to his trailer air brakes, and connect it to the compressed air cylinder 64 during the backing operation, so that it can then be operated from the tractor cab in the same manner as the trailer brakes are normally operated.

The movable lower jaw indicated at 10 preferably has two transversely spaced downwardly extending ears 1| which carry a pivot pin 12 secured in one ear by a set screw 13. The ears 1 I straddle the end portion 56 of the lever 51 adjacent to the ears 53, and the lever is pivotally connected to the lower jaw 18 by the pivot pin 12. The upper surface of the lower jaw 18 has a friction shoe 14 secured thereon, which shoe is preferably T-shaped and has a tongue 15 extending slidably into the rectangular opening formed by the box portion 52 of the upper jaw. The friction shoe 14 is adapted to contact the lower surface of the lower sector plate 4|.

A spacer shoe 18 having T-shape identical to the shoe 14, is located between sector plates 4| and has a tongue 11 fitting slidably into the box opening 52. The upper end lower surfaces of the shoe 18 contact the inner surfaces of the sector plates 4| when the clamping jaws are brought together. A guide bolt 18 extends vertically through the box portion 52, and the tongue portions 15 and 11 of the shoes fit loosely on the bolt 18, so that the shoes can float up and down within the box opening. The bottom end of the bolt 18 is secured in a transverse wall forming the bottom wall of the box opening 52.

When the piston rod 63 of the air cylinder 64 is actuated upwardly, the lever 51 pivots about the pin 54 and raises the lower jaw 10. When the lower jaw 10 is raised, the spacer shoe 11 cooperates with the upper and lower jaws and the resilient sector plates so as to frictionally grip the four surfaces of the sector plates with substantially equal pressure. This clamping action grips the sector plates in a manner similar to the gripping action of a friction brake shoe, so as to prevent relative turning of the undercarriage with respect to the trailer platform.

Obviously, if the plate portion 33 were extended between the jaws of the clamp and the resilient plates omitted, then the shoe 11 would also be omitted and the edge of the plate would be clamped between the upper and lower jaws.

The arrangement of the lever arms is correlated to the amount of air pressure so as to produce a predetermined amount of frictional gripping force calculated adequately to prevent relative turning of the undercarriage under normal turning loads, but to permit some slippage between the shoes and the plates when the turning loads become abnormal and exceed the predetermined amount. This predetermined amount is such that some relative turning is permitted before the tires of the undercarriage are slid sufficiently to cause damage, as would be the a case if the undercarriage were to jackknife during a backing operation.

In backing a tractor-trailer combination of this type, the operator first maneuvers the tractor sufficiently to get the combination started in the general direction in which he wishes to back, and then operates the air cylinder to actuate the clamp. In other words, if he wants to back in a straight line, he clamps the undercarriage with its wheels aligned with the trailer platform; and if he wants to back in a long curve he first gets the trailer platform turned in that direction and then clamps the undercarriage to the trailer. During the backing operation with the undercarriage clamped to the trailer platform, the operator can still make minor corrections in direction by steering the tractor, but if he observes that the trailer is getting too far off direction at any time, he momentarily releases the clamp and realigns the trailer in the proper direction by steering the tractor.

Thus the novel clamping device provides means. operable from the cab of the towing tractor for frictionally clamping the undercarriage of the trailer to the fifth wheel plate to prevent relative turning under normal loads during backing, while permitting some turning under excessive loads.

In the foregoing description, certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiment of the improved construction illustrated and described herein is by way of example, and the scope of the present invention is not limited to the exact details of construction.

Having now described the invention, the construction, the operation and use of a preferred embodiment thereof, and the advantageous new and useful results obtained thereby; the new and useful constructions, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

We claim:

1. In a trailer having a fifth wheel plate and an undercarriage swiveled thereon, spaced resilient extensions on said plate, means on the undercarriage for frictionally clamping said plate and including upper and lower jaws for engaging the outer surface of said extensions, a floating spacer shoe between said extension for engaging the inner surfaces thereof, means rigidly mounting said upper jaw on said undercarriage, lever means on the undercarriage pivotally connected to said lower jaw, and power means for actuating said lever toclamp the jaws and shoe in superposed relation against the inner and outer surfaces of said resilient extensions.

2. In a trailer having a fifth wheel plate and an undercariage swiveled thereon, spaced resilient extensions on said plate, means on the undercarriage for frictionally clamping said plate and including upper and lower jaws for engaging the outer surfaces of said extensions, a floatiing spacer shoe between said extensions for engaging the inner surfaces thereof, means rigidly mounting said upper jaw on said undercar riage, guide means on said upper jaw movably mounting said spacer shoe, lever means on the undercarriage pivotally connected tosaid lower jaw, and power means for actuating said lever to clamp the jaws and shoe in superposed relation against the inner and outer surfaces of said resilient extensions.

3. In a trailer having a fifth wheel plate and an undercarriage swiveled thereon, spaced extensions on said plate, means on the undercarriage for frictionally clamping said plate and including upper and lower jaws for engaging the outer surfaces of said extensions, a floating spacer shoe between said extensions for engaging the inner surfaces thereof, means rigidly mounting said upper jaw on said undercarriage, lever means on the undercarriage pivotally connected to said lower jaw, and power means of actuating said lever to clamp the jaws and shoe in superposed relation against the inner and outer surfaces of said extensions.

4. In a trailer having a fifth wheel plate and an undercarriage swiveled thereon, spaced extensions on said plate, means on the undercarriage for frictionally clamping said plate and including upper and lower jaws for engaging the outer surfaces of said extensions, a floating spacer shoe between said extensions for engaging the inner surfaces thereof, means rigidly mounting said upper jaw on said undercarriage, guide means on said upper jaw movably mounting said spacer shoe, lever means on the undercarriage pivotally connected to said lower jaw, and power means for actuating said lever to clamp the jaws and shoe in superposed relation against the inner and outer surfaces of said extensions.

W. CARL ANDERSON. SYDNEY L. DEWEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 655,562 Lindstrom Aug. 7, 1900 2,466,194 W. C. Anderson et a1. Apr. 5, 1949' 2,468,705 Price Apr. 26, 1949 

